1. Field of the Invention
This invention relates to a composition and method for disinfecting and sterilizing matter contaminated with bacteria, fungi, spores, viruses, and the like.
2. Perspective of the Invention
Institutions such as hospitals, clinics, physicians, biomedical laboratories, food processors, and pharmaceutical and cosmetic industries all utilize liquid sterilization or disinfection methods. The invention is directed to a method for disinfecting and sterilizing various forms of matter where an effective sterilant or disinfectant is needed. Such matter may include medical instruments, examining tables, glassware, doors, windows, walls, solutions, enclosed spaces or chambers such as incubators, laboratory equipment, and the like. Therefore, the invention has potential application for use in all of the above fields and other fields where an effective sterilant or disinfectant is needed. For purposes of illustration only, medical instruments will be exemplified throughout this description.
Medical instrument sterilization procedures provide for the inactivation of infectious microorganisms and are of particular importance in the disinfection and sterilization of reusable and certain disposable medical instruments and devices, implantable devices, and prosthetics. Effective sterilization of these items and equipment for manufacturing medical products is essential. The ongoing AIDS, concomitant tuberculosis (TB), and Hepatitis B epidemics underscore the need for effective broad spectrum appliance sterilization. Patient-to-patient transmission of microbial diseases through contaminated instruments and devices has been reported. Weller, I. et al., 29 Gut 1134 (1988); Hanson, P. & Collins, J., 44 Thorax 778 (1989); Bond, W., 257 J. Am. Med. Ass'n 843 (1987). Such studies have shown the occurrence of diverse infectious agents in medical devices, particularly of HIV in fiberoptic bronchoscopes. These studies indicate a possible cause of nosocomial infections is inadequately sterilized medical devices that undergo multiple uses. Favero, M. & Bond, W., Sterilization, Disinfection, and Antisepsis in the Hospital, Manual of Clinical Microbiology 183-200 (American Society of Microbiology, 1989).
Pathogenic infections and the resulting complications due to contaminated devices are difficult to ascertain. The data tend to be under-reported because of long incubation times and removal of patients from the exposure site. Incidences of infection of 6% for pneumonia, 30% for bacteriemia, and 46% for fever after bronchoscopies have been shown. Pereira, W., et al., 112 Am. Rev. Resp. Dis. 59 (1975); Burman, S., 40 J. Thoracic and Cardiovas. Surg. 635 (1960). Although bronchoscope contamination seems to be the best documented, several other medical devices have also been related to transmission of disease. Transmission of hepatitis by contaminated medical devices has long been a concern of surgeons and clinicians. Bacterial contamination inside a spirometer after one week's use has been measured at one-hundred million (10.sup.8) organisms per milliliter. Houston et al., 12 Breath 10 (1981). Some models of ventilators and respirators are also suspect in the transmission of infectious microorganisms.
Sterilization procedures are necessarily directed toward the destruction of ubiquitous microbes. Some bacterial spores are extremely resistant to heat and require heating in steam under pressure at greater than 120.degree. C. for as long as eleven hours to insure destruction. Most spores are not this resistant, however, and are killed by moist heat at greater than 120.degree. C. for thirty minutes. Bacterial spores are also very resistant to bactericidal compounds. For many commonly used disinfectants, such as hypochlorite and phenols, concentrations one-thousand to ten-thousand times greater are needed to kill spores than are needed to kill vegetative cells. An exception to this generalization is alkalating agents, such as ethylene oxide or formaldehyde, where one-half to fifteen times as much alkalating agent is needed to kill spores than is needed to kill vegetative cells. Therefore, a sporicidal agent that is capable of sterilizing a wide range of medical devices and instruments in a simple and straight forward fashion is desirable.